JPH05220795A - Metal mold device for molding disk substrate - Google Patents

Abstract

PURPOSE:To form a tip face as a mounting reference face to a disk rotation drive means and form a disk substrate having a protrusion with a punched hole at the central part with a high accuracy and without generating mold distortion. CONSTITUTION:A sliding member 48 forming a peripheral face of a disk substrate is arranged on a periphery of a moving side metal mold 32 movably back and forth. When a disk substrate molding cavity 34 is filled with synthetic resin material, the sliding member 48 is moved relatively with respect to the moving side metal mold 32 and is made to strike a fixed side metal mold 31 so as to prevent generation, on the periphery of the molding cavity 34, of clearance where the synthetic resin material might penetrate. Further, by providing a mold release resistant section on the moving side metal mold 32, after the disk substrate is molded, when a mold opening is performed, the molded disk substrate 2 is held by the mold release resistant section and is released from a stamper face 40 mounted on the fixed side metal mold 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk substrate molding die apparatus for molding a disk substrate made of a synthetic resin material which constitutes a disk as an information signal recording medium such as an optical disk or a magneto-optical disk.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an optical disk using a disk substrate formed of a synthetic resin material such as a polycarbonate resin having a light transmitting property. Known optical discs of this type include a reproduction-only optical disc that only reproduces a pre-recorded information signal and a rewritable magneto-optical disc that enables rewriting of the information signal once recorded. .. In a read-only optical disc, a reflective film formed by, for example, vapor deposition of aluminum or the like is formed on one main surface side of the disc substrate on which a so-called pit, which is a concavo-convex pattern corresponding to an information signal such as a predetermined tone signal, is formed. It is provided and configured. In addition, a magneto-optical disk capable of rewriting information signals has a signal recording layer having a magnetic film on one main surface of a disk substrate on which pregrooves forming recording tracks for recording desired information signals are formed. It is formed and configured.

This type of optical disc can record information signals such as digitized tone signals at extremely high density. Therefore, the applicant of the present application has proposed an optical disc having a diameter of 64 mm and capable of recording and reproducing a musical tone signal of at least 74 minutes or only reproducing.

As shown in FIG. 13, the optical disk 1 has a disk substrate 2 formed by molding a synthetic resin material such as a polycarbonate resin having a light transmitting property, and one main surface side of the disk substrate 2 is formed. A signal recording layer is formed by depositing a perpendicular magnetization film or the like on. Then, the recording of the information signal on the optical disc 1 is emitted from the optical pickup to a recording track provided in a signal recording portion having a signal recording layer in a state where the optical disc 1 is rotationally driven at a predetermined rotation speed. This is performed by irradiating a light beam and applying an external magnetic field that is magnetic field modulated according to the information signal to be recorded from the external magnetic field generator.

Since the optical disc 1 has a small diameter and fine recording tracks formed at a high density, as shown in FIG. 14, the optical disc 1 is arranged in a disc recording and / or reproducing apparatus for rotating the optical disc 1. The disc rotation drive mechanism 3 is mounted on the disc table 4 while being accurately positioned and mounted on the disc table 4 in a surely integrated manner. The disc table 4 is precisely synchronized with the rotation of the disc table 4. It needs to be rotated.

Therefore, the disk table 4 is formed at the center of the other main surface 2c of the main body 2a of the substrate 2a on which the signal recording layer of the disk substrate 2 constituting the optical disk 1 is formed. A projecting portion 8 having a mounting reference surface 7 for accurately positioning the mounting height position formed on the tip surface is provided in a protruding manner. The protrusion 8 has a centering member engaging hole 6 at the center thereof, with which a centering member 5 for centering the optical disc 1 mounted on the disc table 4 is engaged. It is perforated and formed into a ring shape. The centering member engagement hole 6 is formed so as to communicate with the center hole 6a formed in the substrate body 2a.

A thin metal plate 9 is arranged on one main surface 2b side of the disk substrate 2 so as to close the center hole 6a. The metal plate 9 is for attracting the magnet 10 arranged on the disc table 4 side to integrate the optical disc 1 mounted on the disc table 4 with the disc table 4.

As shown in FIG. 14, the optical disc 1 thus constructed has the centering member engaging hole 6 engaged with the centering member 5 and the mounting reference surface 7 formed on the tip end surface of the projecting portion 8. Is supported by the disk supporting surface 4a of the disk table 4, and the metal plate 9 is attracted by the magnet 10 and mounted on the disk table 4, so that the center of the disk table 4 coincides with the center of rotation of the disk table 4 and is mounted. It is mounted on the disc table 4 after being positioned at a height position and securely integrated.

The disc substrate 2 constituting the optical disc 1 is formed by molding a synthetic resin material such as a polycarbonate resin with a die device for injection molding. As a mold device for molding the disk substrate 2, a mold device configured as shown in FIG. 15 has been proposed. This mold device is arranged to face the fixed-side mold 11 and the fixed-side mold 11 so as to face each other, and to move back and forth in the direction of approaching and separating from the fixed-side mold via a hydraulic mechanism or the like. The molding die 13 is composed of the movable-side die 12 supported by the molding die 13. Fixed-side mold 1 constituting this molding mold 13
A disk substrate 2 to be molded between the movable mold 1 and the movable mold 12.
The molding cavity 14 corresponding to is defined.

At the center of the molding cavity 14 on the fixed mold 11 side, a synthetic resin material such as a melted polycarbonate resin supplied from an injection molding machine is placed in the molding cavity 4. A sprue bush 15 for inflow is arranged. A resin injection port 16 is bored in the sprue bush 15, and the molten synthetic resin material supplied from the injection molding machine is injected into the molding cavity 14 through the resin injection port 16 and filled. ..

The molding surface 11a, which defines the molding cavity 14 of the fixed-side mold 11, serves as a light beam incident surface side and is a smooth surface with high precision, and the other main surface 2c of the disk substrate 2 is formed. The mirror surface is made to be a highly accurate and smooth surface so as to enable the molding. Further, on the outer peripheral side of the sprue bush 15, the disc substrate 2
The recessed portion 1 for forming a protruding portion for forming a protruding portion 8 having a mounting reference surface 7 formed on the other main surface 2c side at the tip surface thereof.
A nesting 18 that constitutes 7 is provided.

On the other hand, on the side of the molding surface 12a that defines the molding cavity 14 of the movable mold 12, the optical disk 1 is provided.
A stamper 19 for forming a so-called pit, which is a minute concave-convex pattern corresponding to the information signal recorded in, or a pre-groove forming a recording track formed in the signal recording portion of the optical disc 1 is mounted. This stamper 19 has a center hole 22 in a fitting projection 21 provided on the tip side of a stamper holder 20 arranged in the center of the movable mold 12.
And the outer peripheral edge side is supported by the outer peripheral side stamper retainer 23 and is mounted on the molding surface 12a side of the movable side mold 12.

The inner peripheral surface side of the claw portion 23a for suppressing the stamper 19 of the outer peripheral side stamper retainer 23 is a molding surface for molding the outer peripheral surface of the disk substrate 2 molded in the molding cavity 14.

Further, a punching punch 24 for punching a centering member engaging hole 6 formed at the center of a protrusion 8 provided on the disk substrate 2 is disposed on the inner peripheral side of the stamper holder 20. ing. The punching punch 24 is inserted into a sleeve 25 arranged on the inner peripheral side of the stamper holder 20 so as to be able to move forward and backward. Between the sleeve 25 and the stamper holder 20, the stamper 17 has an air passage 26 for release air for releasing the molded disk substrate 2 from the movable mold 12 in which the stamper 17 is arranged.
Are formed.

In order to mold the disk substrate 2 using the mold device constructed as described above, the movable mold 12 is brought into close proximity to the fixed mold 11 side and the mold is clamped. In this mold clamped state, the resin injection port 1 of the sprue bush 15
A synthetic resin material such as a melted polycarbonate resin supplied from an injection molding machine is injected and filled into the molding cavity 14 via 6. At this time, punching punch 2
4 is moved to form a centering member engagement hole 6.
Next, the movable side mold 12 is moved to the fixed side mold 11 side, and the mold is clamped to compress the synthetic resin material filled in the molding cavity 4 and the cooling is performed.
The disk substrate 2 corresponding to the molding cavity 14 is molded. After that, the movable side mold 12 is moved in a direction away from the fixed side mold 11 and the mold opening is performed through the air passage 26 to the mold cavity 14 to move the molded disk substrate 2. The disc substrate 2 is molded by releasing from the side mold 12 and taking out the molding mold 13 to the outside using a predetermined take-out mechanism.

[0016]

DISCLOSURE OF THE INVENTION By the way, as described above, the disc substrate 2 is provided by a die apparatus in which a punching punch 24 for punching the centering member engaging hole 6 is provided on the movable die 12 side on which the stamper 19 is arranged. 16, the punching burr 27 is apt to occur on the periphery of the centering member engaging hole 6 on the mounting reference surface 7 side at the tip of the protruding portion 8 which is the tip side in the punching direction of the punching punch 24. Have.

Then, as described above, the disk substrate 2
The peripheral edge of the centering member engagement hole 6 on the mounting reference surface 7 side is a portion where the outer peripheral surface of the centering member 5 abuts to achieve centering. The surface serves as a surface for positioning the position. Therefore, the optical disc 1 configured by using the disc substrate 2 having the punching burr 27 on the peripheral edge of the centering member engagement hole 6 on the mounting reference surface 7 side has a highly accurate relationship between the centering member engagement hole 6 and the centering member 5. If the optical disc 1 is mounted on the disc table 4, the optical disc 1 is not centered, and the disc table 4 is mounted without positioning the mounting position. The optical disc 1 mounted in such a state remains eccentric and is driven to rotate due to surface wobbling, which makes it impossible to accurately record and / or reproduce information signals. It will be possible.

As described above, the bulging portion 8 of the disk substrate 2
In order to prevent the punching burr 27 from being generated at the peripheral edge of the centering member engagement hole 6 on the mounting reference surface 7 side of the tip, a die device for molding a disk substrate configured as shown in FIG. 17 is proposed. Has been done.

Contrary to the above-described mold device, this mold device has a stamper 17 on the stationary mold 11 side and a centering member engagement on the movable mold 12 side, as shown in FIG. By disposing the punching punch 24 for punching out the hole 6, the centering member engaging hole 6 is punched from the mounting reference surface 7 side of the disc substrate 2, and the centering member engaging hole 6 on the mounting reference surface 7 side is provided with a peripheral edge. It is configured so that punching burrs do not occur.

In the die unit shown in FIG. 17, the punching punch 24 is arranged in the center of the movable die 12 and constitutes the sleeve 2 for forming the projection forming recess 17.
It is arranged so as to advance and retreat within 8. This sleeve 2
8 is configured to be movable back and forth so that the molded disk substrate 2 is released from the movable mold 12.

However, in the mold device shown in FIG. 17, the stamper 19 and the outer periphery for supporting the stamper 19 on the stationary mold 11 when the molten synthetic resin material is filled in the molding cavity 14. A part of the synthetic resin material enters between the side stamper retainer 23 and the side stamper retainer 23, and burrs 29 are generated on the outer peripheral edge side of the disk substrate 2 molded as shown in FIG. When the burr 29 that is held between the stamper 19 and the outer peripheral side stamper retainer 23 is generated in this way, the mold release resistance from the fixed side mold 11 side on which the stamper 19 is mounted becomes extremely large, and the molded disc substrate 2 cannot be reliably released from the stamper 19.

In this way, when the release resistance becomes large and it becomes impossible to release the stamper 19 easily,
Molding distortion is generated in the molded disk substrate 2, and polarization abnormality is generated, so that it cannot be used as the disk substrate 2 of the optical disk. Further, when the molded disk substrate 2 is not easily released from the stamper 19 mounted on the stationary mold 11, it becomes difficult to open the mold and remove it from the molding mold 13. I will end up.

A part of the synthetic resin material penetrates between the stamper 19 and the outer peripheral side stamper retainer 23 supporting the stamper 19, and a burr 29 is formed on the outer peripheral edge side of the disk substrate 2.
And making it difficult to release the molded disk substrate 2 from the stamper 19 also occurs in the mold apparatus shown in FIG.

In order to prevent such a mold release defect of the molded disk substrate 2 from the stamper 19, it is conceivable to inject compressed air for mold release between the disk substrate 2 and the stamper 19. It becomes extremely difficult to evenly inject compressed air onto the main surface of the molded disc substrate 2, and reliable mold release cannot be performed.

Therefore, according to the present invention, in forming a disk substrate having a protrusion having a hole at the center thereof, the main surface of the substrate main body having the front end surface side as a mounting reference surface for the disk rotation driving means, The molding precision is high to prevent the occurrence of burrs that hinder the molding precision in the part where the mounting reference surface is formed, and it enables the molding of the disk substrate without causing molding distortion and simplifies the device itself. The present invention has been proposed for the purpose of providing a mold device for molding a disk substrate that can achieve the above.

[0026]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a substrate main body having minute irregularities or grooves formed on one main surface side and the other main body of the substrate main body. In a die device for molding a disk substrate, a disk substrate is formed so as to project toward the surface side, the tip surface side serves as a mounting reference surface for the disk rotation driving means, and a disk substrate is provided with a projecting portion having a hole in the center. A fixed-side mold that constitutes the disk substrate molding cavity; a movable-side mold that is arranged opposite to the fixed-side mold and that constitutes the disk substrate molding cavity together with the fixed-side mold; A stamper for molding minute irregularities or grooves arranged on the disk substrate molding surface side of the fixed mold,
A punching punch for punching a hole in a protruding portion of the disk substrate provided in the movable die, and an outer peripheral surface of the disk substrate which is provided so as to be able to move forward and backward on the outer peripheral side of the movable die. A sliding member, and a mold release resistance portion of the disk substrate molded on at least one of the movable mold and the sliding member.

[0027]

The mold apparatus for molding a disk substrate according to the present invention is configured such that when a molten synthetic resin material is filled in a disk substrate molding cavity formed between a fixed mold and a movable mold, this molding is performed. The movable mold is moved in the direction away from the fixed mold by the pressure of the synthetic resin material.
At this time, the sliding member which is arranged on the outer peripheral side of the movable side mold so as to be able to move forward and backward and forms the outer peripheral surface of the disk substrate is moved relative to the movable side mold and abuts against the fixed side mold side. Therefore, it is possible to prevent the formation of a gap into which the synthetic resin material intrudes on the outer peripheral side of the molding cavity.

Further, after molding the disk substrate, when the mold opening for moving the movable side mold in one direction separating from the fixed side mold is performed, the molded disk substrate becomes a release resistance portion. It can be held and released from the stamper surface.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of a disk substrate molding die apparatus according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the disc substrate molding die apparatus according to the present invention includes a molding die 33 composed of a fixed-side die 31 and a movable-side die 32, which are arranged to face each other. The fixed side mold 31 and the movable side mold 32 which constitute this molding mold 33
A molding cavity 34 corresponding to the disk substrate 1 to be molded is defined between them.

The fixed-side die 31 is supported by the fixed mounting base 36 via mounting means (not shown).
Further, the movable side mold 32, which is moved in the direction of approaching and separating from the fixed side mold 31, is supported on a movable mounting base 37 driven by a driving means such as a hydraulic drive mechanism via a mounting means (not shown). It will be done.

On the fixed side die 31 side, a synthetic resin material such as a melted polycarbonate resin supplied from an injection molding machine is located in the center of the molding cavity 34 and is injected into the molding cavity 34. A sprue bush 39 having a resin injection port 38 for injection and filling is provided. Then, the molten synthetic resin material supplied from the injection molding machine is injected into the molding cavity 34 through the resin injection port 38.

On the side of the molding surface 31a forming the molding cavity 34 of the fixed-side mold 31, a so-called pit or a recording track of the optical disk 1 which is an uneven pattern corresponding to an information signal recorded on the optical disk 1 is formed. A stamper 40 for molding the constituent pregrooves is mounted. The stamper 40 is formed in a disk shape having a center hole 40a at the center.

The stamper 4 is provided on the outer peripheral side of the sprue bush 39 arranged in the center of the stationary mold 31.
A stamper holder 41 for positioning and supporting 0 is fitted and arranged. This stamper holder 41 has a center hole 4 of the stamper 40 on the tip side protruding toward the molding cavity 34.
A fitting protrusion 42 to which 0a is fitted is provided. The fitting protrusion 42 is formed in a cylindrical shape having an outer diameter substantially the same as that of the center hole 40a so that the center hole 40a of the stamper 40 can be fitted closely. That is, the outer peripheral surface of the fitting protrusion 42 serves as a mounting position regulation surface that positions the mounting position of the stamper 40 mounted on the fixed mold 31 side. Therefore,
By fitting the center hole 40a into the fitting protrusion 42, the stamper 40 can be mounted by being centered with respect to the fixed-side mold 31.

Further, the stamper 40 is supported on the outer peripheral side by the stamper pressing portion 43a of the outer peripheral side stamper presser 43 which is fitted and arranged on the outer peripheral side of the fixed side mold 31, whereby the fixed side mold 31 is supported. It is closely supported by the molding surface 31a.

The tip side of the stamper holder 41, which projects into the molding cavity 34, projects toward the other main surface 2c of the disk substrate 2 with a thickness substantially the same as that of the substrate holder 2a. A protruding portion forming portion 44 is formed to form the protruding portion 8 having the mounting reference surface 7 formed at the front end surface.

On the other hand, at the center of the molding surface 32a defining the molding cavity 34 of the movable mold 32, a protrusion formed at the tip side of the stamper holder 41 arranged in the fixed mold 31 is formed. The disk substrate 2 in cooperation with the molding unit 42
A protrusion-forming recess 45 for forming the protrusion 8 formed on the other main surface side is formed. A punching punch 46 having a punching punch function for punching out a centering member engaging hole 6 formed as a punched hole in the central portion of the projecting portion 8 is provided in the central portion of the projecting portion forming concave portion 45. .. The punching punch 46 has a protruding portion 8
Mounting reference surface molding surface 47 for molding the mounting reference surface 7 of the front end surface
It moves back and forth in the sleeve 47 having a tip end surface.

The sleeve 47 is a movable mold 3
It has a function of ejecting the molded disk substrate 2 supported by the movable mold 2 from the movable side mold 32.

On the outer peripheral side of the movable side mold 32, the outer peripheral side of the molding cavity 24 is defined, and a ring-shaped sliding member for molding the outer peripheral side peripheral surface 2d of the disk substrate 2 to be molded. 48 are provided. The sliding member 48 includes a step portion formed on the outer peripheral side of the movable die 32 and a sliding member holding member arranged on the outer peripheral side of the movable die 32 so as to surround the outer peripheral side of the step portion. It is arranged so as to be able to move forward and backward in a sliding member housing portion 50 formed by the member 49. Then, the sliding member 48 has a sliding member storage portion 50.
The fixed side mold 31 side is moved relative to the movable side mold 32 by the compressed air supplied through the air passage 51 formed in the movable side mold 32 with the opening 51a facing the bottom face of the fixed side mold 31. Be advanced to.

The sealing O-rings 52 and 53 are provided on the inner peripheral surface of the sliding member housing portion 50 on the movable mold 32 side and the outer periphery of the sliding member 48, and the compression is supplied. The inside of the sliding member accommodating portion 50 is sealed so that air does not leak.

As shown in FIG. 2, the other main surface of the disk substrate 2 to be molded is formed on the inner peripheral surface of the projecting portion molding concave portion 45 formed in the movable side mold 32 having the above-described structure. Two
Engaging projections 55 that project and engage with the outer peripheral surface of the projections 8 that project on the c side are projected. In other words, the engaging projections 55 project the disk substrate 2 and then the projections 8 of the disk substrate 2 when the movable mold 32 is moved in a direction in which the movable mold 32 is separated from the fixed mold 31. Is a mold release resistance portion that is engaged with the outer peripheral surface of the and is held on the movable side mold 32 side. A plurality of the engagement protrusions 37 are provided in a ring shape or at predetermined intervals on the inner peripheral surface of the protrusion forming recess 45.

The engagement projection 55 is formed from the bottom surface of the projection forming recess 45 so as not to affect the molding of the mounting reference surface 7 formed on the tip surface of the projection 8 of the disk substrate 2. It is provided at the position of the inner peripheral surface which is separated from each other.

Further, the inner peripheral surface 48 of the sliding member 48 disposed on the outer peripheral side of the movable mold 32 on the molding cavity 34 side.
As shown in FIG. 3, the tip on the a side also projects and engages with the outer peripheral surface 2d side of the substrate body 2a of the disk substrate 2 to be molded, and when the mold is opened after molding the disk substrate 2, Engaging projections 56 are provided so as to function as mold release resistance portions that hold the disk substrate 2 on the movable side mold 32 side. A plurality of the engagement protrusions 56 are also provided on the inner peripheral surface 48a of the sliding member 48 in a ring shape or at predetermined intervals.

In order to mold the disk substrate 2 using the mold device having the above-described structure, as shown in FIG.
The movable mold 32 is brought into close proximity to the fixed mold 31 side, and the mold is clamped. When this mold is clamped, the air passage 51
Compressed air is supplied into the sliding member accommodating portion 50 via the, and the sliding member 48 is urged to advance to the fixed side mold 21 side.

Then, in the mold clamped state, as shown in FIG. 5, into the molding cavity 34 through the resin injection port 38 of the sprue bush 39, such as molten polycarbonate resin supplied from the injection molding machine. A synthetic resin material is injected and filled. When the synthetic resin material is filled in the molding cavity 34, the movable mold 32 is moved in a direction away from the fixed mold 31 by the pressure of the filled synthetic resin material. At this time, the sliding member 48, which is urged to move toward the fixed-side mold 21 side by receiving the pressure of the compressed air, moves relative to the movable-side mold 32, as shown in FIG. It is pressed against the surface of the stamper 40 arranged on the stationary mold 21.

When the molding cavity 34 is filled with the synthetic resin material, the punching punch 47 is moved to form the centering member engaging hole 6 at the center of the projection 8.

By the way, since the abutting surface 48a, which is the upper end surface side of the sliding member 48, against the stamper 40 is a flat surface, the sliding member 48 and the stamper 40 are pressed against the surface of the stamper 40. A gap such that a part of the synthetic resin material infiltrates therein is prevented from occurring, and burr is prevented from occurring on the outer peripheral side of the disk substrate 2 to be molded.

After filling the synthetic resin material into the molding cavity 34 as described above, the movable side mold 32 is moved to the fixed side mold 31 side again as shown in FIG. Mold clamping is performed to compress the filled synthetic resin material to prevent sink marks or the like from occurring on the disk substrate 2 to be molded.

After that, after cooling the molding die 33 to cure the disk substrate 2 to be molded, as shown in FIG. 8, a mold opening for separating the movable side mold 32 from the fixed side mold 31 is performed. By doing so, the molding of the disk substrate 2 is completed. When the mold is opened, the sleeve 47 is pushed out toward the inside of the molding cavity 34,
The molded disc substrate 2 is released from the movable die 32 and taken out of the molding die 33 by a predetermined take-out mechanism.

By the way, when the synthetic resin material is molded, the disk substrate 2 is formed with the engaging protrusion 55 protruding from the inner peripheral surface of the protrusion forming recess 45 formed in the movable mold 32. The engaging projection 56, which is engaged with the outer peripheral surface of the protrusion 8 of the sliding member 48, and is further engaged with the outer peripheral surface 2d of the substrate body 2a, which is provided on the inner peripheral surface 48a side of the molding cavity 24 side of the sliding member 48. Becomes Here, when mold opening is performed in which the movable side mold 32 is moved in a direction away from the fixed side mold 31, the molded disc substrate 2 is held by the engaging projections 55 and 56, and the movable side mold 32 is moved. Following the die 22, it is released from the surface of the stamper 29 provided on the stationary die 21.

Therefore, the engaging projections 55 and 56 are
The height and size are set so as to have a releasing resistance larger than the releasing resistance with respect to the stamper 40 arranged on the fixed side die 21 of the disk substrate 2. By providing the engaging protrusions 55 and 56 in this way, the molded disk substrate 2 is reliably released from the stamper 40 side,
The stamper 29 can be reliably moved to the movable mold 22 side where the stamper 29 is not provided.

Then, the disk substrate 2 molded by the mold device provided with the engaging projections 55 and 56 as described above.
As shown in FIG. 9, a concave groove 8a is formed as a detached resistance portion corresponding to the engaging projection 55 of the projection 8. The concave groove 8a is formed on the outer peripheral surface of the projection 8. Since it is formed, it is possible to perform highly accurate and smooth molding without causing burrs or the like on the mounting reference surface 7 of the tip end surface that needs to be accurately and smoothly formed.

Further, the substrate body 2a of the disk substrate 2 is formed with a concave groove 2d as a detached resistance portion corresponding to the engaging projection 56 provided on the sliding member 48. This concave groove 2d. As shown in FIG. 10, since the signal recording portion of the substrate main body 2a is formed on the outer peripheral surface which is the outer peripheral side edge where the signal recording portion is not formed, there is no influence on the substrate main body 2a on which the signal recording portion is formed. Can be suppressed.

Furthermore, in the mold apparatus shown in FIG.
Since the punching punch 46 is arranged on the side of the movable die 32 in which the projection forming recess 45 for forming the mounting reference surface 7 formed on the tip end surface of the projection 8 is formed, the center of the projection 8 is formed. The centering member engagement hole 6 formed in the portion is formed from the mounting reference surface 7 side as shown in FIG. Therefore, the mounting reference surface 7 can be formed as a smooth surface with high precision without generating a punching burr by the punching punch 46 on the mounting reference surface 7 side, and the centering member 5 is engaged with the centering member engaging hole 6. It is possible to form the peripheral edge of the side to be formed with high precision.

In the above-described embodiment, the sliding member 48 is biased by compressed air in the direction in which it projects from the movable side mold 32. However, a biasing member such as a spring is used without using such compressed air. May be used to urge the movable side mold 32 in the direction of protruding.

Further, engaging projections 55 and 56 are provided on the inner peripheral surface of the projection forming concave portion 45 and the inner peripheral surface 48a of the sliding member 48, respectively, but on the fixed side where the stamper 29 is arranged. If it is possible to secure a mold release resistance larger than the mold release resistance from the mold 21 side, it may be provided only on one of them.

Further, in the above-mentioned embodiment, the engaging projection 55 which is formed on the inner peripheral surface of the projection forming concave portion 45 and which is formed on the inner peripheral surface of the projection forming concave portion 45 and projects toward the disk substrate 2 side is provided. ,
It is sufficient that the release resistance of the disc substrate 2 at the time of release is obtained, and as shown in FIG.
Engaging recess 58 such that a part of the outer peripheral surface of the
It may be formed as.

[0057]

The mold apparatus for molding a disk substrate according to the present invention is provided with a sliding member which is arranged on the outer peripheral side of a movable mold so as to be capable of advancing and retracting and which molds the outer peripheral surface of the disk substrate. Therefore, the melted synthetic resin material is filled in the disk substrate molding cavity formed between the fixed side mold and the movable side mold, and the movable side mold is fixed by the pressure of the filled synthetic resin material. When moved in a direction away from the mold, the sliding member is moved relative to the movable mold and abutted against the fixed mold side, and the synthetic resin material enters the outer peripheral side of the molding cavity. Since such a gap is prevented from being generated, it is possible to prevent a burr from being generated on the outer peripheral edge side of the disk substrate to be molded, and it is possible to suppress the occurrence of a mold release defect at the time of mold release.

Further, since the mold release resistor is provided on the movable side mold, when the mold is opened after the mold of the disc substrate is performed, the molded disc substrate is held by the mold release resistor. As a result, reliable release from the stamper surface mounted on the fixed side mold side is achieved.

Therefore, it is possible to prevent the mold release failure due to the mounting of the stamper on the fixed side mold, to prevent the molding distortion and the like from occurring in the disk substrate to be molded, and to configure the tip surface of the protruding portion. This makes it possible to form the mounting reference surface with high precision and to easily take out the formed disc substrate from the mold.

Furthermore, since it is not necessary to use compressed air in order to release the molded disk substrate from the mold, it is not necessary to provide an air passage or the like in the mold. Can be done easily.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a mold device for molding a disk substrate according to the present invention.

FIG. 2 is a partial cross-sectional view showing an engagement protrusion that constitutes a release resistance portion formed on the inner peripheral surface of a protrusion forming recess.

FIG. 3 is a partial cross-sectional view showing an engagement protrusion that constitutes a release resistance portion formed on a sliding member.

FIG. 4 is a schematic cross-sectional view of a mold device for molding a disk substrate according to the present invention, showing a mold clamping state in which a movable mold is moved to a fixed mold side.

FIG. 5 is a schematic cross-sectional view of a mold device for molding a disk substrate according to the present invention, showing a state where a synthetic resin material is injected into a molding cavity.

FIG. 6 is a schematic cross-sectional view of a mold device for molding a disk substrate according to the present invention, showing a state in which a molding cavity is filled with a synthetic resin material.

FIG. 7 is a schematic cross-sectional view of a mold device for molding a disk substrate according to the present invention, showing a state in which a molding cavity is filled with a synthetic resin material and then compressed.

FIG. 8 is a schematic cross-sectional view of a mold device for molding a disk substrate according to the present invention, showing a mold open state in which a movable mold is separated from a fixed mold.

FIG. 9 is a partial perspective view showing a protruding portion of a disk substrate molded by a mold device for molding a disk substrate according to the present invention.

FIG. 10 is a partial perspective view showing an outer peripheral side portion of a substrate main body of a disk substrate molded by a mold device for molding a disk substrate according to the present invention.

FIG. 11 is a schematic cross-sectional view showing a state in which a centering member engagement hole is punched in a protruding portion of a disc substrate by a punching punch arranged in a die device for molding a disc substrate according to the present invention.

FIG. 12 is a partial cross-sectional view showing another example of the mold release resistance portion formed on the inner peripheral surface of the projection forming recess.

FIG. 13 is a partially cutaway perspective view showing an optical disc formed by using a disc substrate formed by molding a synthetic resin material.

FIG. 14 is a cross-sectional view showing a state where the optical disc is mounted on a disc rotation drive mechanism.

FIG. 15 is a schematic cross-sectional view showing a mold device for molding a disk substrate prior to the present invention.

16 is a partial cross-sectional view showing, in an enlarged manner, a protruding portion of a disk substrate molded by the mold device for molding a disk substrate shown in FIG.

FIG. 17 is a schematic cross-sectional view showing another example of the mold device for molding a disk substrate prior to the present invention.

18 is a schematic cross-sectional view showing an outer peripheral edge side portion of the disc substrate showing a state where the disc substrate is molded by the mold device for molding the disc substrate shown in FIG.

[Explanation of symbols]

 2 disk substrate 6 centering member engaging hole 7 mounting reference surface 8 protrusion 31 fixed side mold 32 movable side mold 34 molding cavity 40 stamper 45 protrusion forming recess 46 punch for punching centering member engaging hole 48 sliding Moving member 55, 56 Engagement protrusion that constitutes the release resistance part

Claims (1)

[Claims] 1. A substrate main body having minute irregularities or grooves formed on one main surface side, and a protrusion formed on the other main surface side of the substrate main body, the front end surface side of which is mounted on a disk rotation driving means. In a mold for molding a disk substrate, which molds a disk substrate having a protruding portion having a hole in the center portion and forming a reference surface, a fixed side mold forming a disk substrate molding cavity and a fixed side A movable mold which is arranged opposite to the mold and constitutes a disk substrate molding cavity together with the fixed mold, and minute irregularities arranged on the disk substrate molding surface side of the fixed mold. Alternatively, a stamper for forming a groove, a punching punch for punching a hole in a protruding portion of a disk substrate arranged on the movable side mold, and a movable punch arranged on the outer peripheral side of the movable side mold. A mold for molding a disk substrate, comprising a sliding member for molding the outer peripheral surface of the disk substrate, and comprising a mold release resistance portion of the disk substrate molded on at least one of the movable side mold and the sliding member. apparatus.